It is known that electronic products in operation produce electromagnetic interference (EMI), noises, including shot noise, flicker noise, surge noise, thermal noise, partition noise, etc., as well as high temperature. Most of the noises are produced due to electromagnetic interference and have adverse influences on the stability of the whole electronic system. It is difficult to completely overcome the electromagnetic interference, which must be, however, reduced to be lower than a standard value through proper circuit design or shielding and grounding structures for the electronic elements, so as to achieve the purpose of electromagnetic compatibility.
In a conventional chip packaging structure, a chip is positioned on a chip pad and a leadframe is provided at each lateral side of the chip to electrically connect with external elements. Each leadframe includes a plurality of sequentially arranged leads, which are connected to contacts on the chip via gold wires. An insulating sealing material is applied to enclose the chip and thereby protects and locates the chip, the gold wires, and other internal elements in place. However, the above-described conventional chip packaging structure does not include any structural design for preventing electromagnetic interference to meet the high standard of electromagnetic compatibility required by current electronic products.